mfd: Fix 88PM8607 I2C dependency

88PM8607 depends on I2C and MFD_CORE. Since 88PM8607 is built-in
kernel, it also requires that I2C and MFD_CORE are built-in
kernel also.
Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/mfd/Kconfig

@@ -321,7 +321,7 @@ config EZX_PCAP
 
 config MFD_88PM8607
 	bool "Support Marvell 88PM8607"
-	depends on I2C
+	depends on I2C=y
 	select MFD_CORE
 	help
 	  This supports for Marvell 88PM8607 Power Management IC. This includes